The invention relates generally to speed control arrangements for electrically powered vehicles such as, for instance, golf carts and light industrial vehicles. In particular, the invention relates to speed controlling arrangements for battery powered electrically driven vehicles including direct current motors.
In the past, some electrically driven vehicles have included direct current motors which have been connected to the drive wheels through direct drive arrangements, such as a "V" belt drive. In such arrangements, the vehicle speed was controlled by varying the voltage applied to the motor, either by selectively inserting and withdrawing resistors in the motor circuit or by differentially connecting the batteries to the motor. These arrangements permitted limited variation in speed at incrementally spaced levels, but were either energy wasteful or involved relatively complicated switching devices.
In at least one prior vehicle, a direct current electric motor was connected to the drive wheels through a variable speed "V" belt drive. However, speed control was provided by control of the voltage applied to the motor. As in the prior vehicles including a direct drive from the motor to the drive wheels, speed could be incrementally varied and the control arrangement was either energy wasteful or included relatively expensive switching arrangements for the batteries.
In other prior vehicles, internal combustion engines were employed as the prime mover, which internal combustion engines were connected to the drive wheels through variable speed "V" belt drives. In these vehicles, vehicle speed was controlled by regulating the engine throttle and a generally continuous and infinite speed control was provided.
Infinite speed control can also be obtained in a direct current motor by employing a potentiometer arrangement for infinitely varying the amount of resistance employed in series with the motor. However, such arrangements are both expensive and energy inefficient. Thus, while infinite control of vehicle speed has been available in internal combustion engine driven vehicles, such infinite and continuous speed control has not been economically available in electrically powered vehicles.